Boron
Introduction Boron is element 5 in the periodic table. Electrons and Bonding Boron has 3 valence electrons. Thus, it tends to form 3 bonds, but occasionally 4 or even 6 with hydrogen and oxygen. A Theoretical Pursuit These articles are based around theoretical, not actual, chemistry. Boron Chain Chemistry Introduction Organic chemistry involves carbon, but as in alternative biochemistries, (say) boron can replace it. The hydrocarbon series is replaced with the "hydroborons," which are divided into "boranes" and "borenes" (with no alkyne analogue covered, as boron can usually only form 3 bonds, whereas carbon can form 4). Systematic Naming of Hydroborons Basic For n = 1 boron, the compound is borane. For n = 2 boron, the compounds are B2H4 borethane and B2H2 borene with a B-B double bond. For n = 3 boron, the boranes are (cyclo)-monoboryl-ane/ene(-ane/-ene and cyclo- are used analogously to in the hydrocarbons). For n ≥4 boron, the straight-chain boranes are (cyclo)-prefix representing n-2-borylane. Borenes beyond Monoborylene The position of the boron immediately to the "left" of the double bond is indicated by a prefixed number (where the double bond is as close to the "left" of the diagram as possible disregarding reflection/rotation) If there are m'' ≥2 double bonds in the compound, it is called a bore-[Greek/Latin prefix representing ''m]-ene. m'' prefixed numbers are attached before the Greek/Latin prefix representing ''m ''when the boron chain length is at least 2''m+1. Substituent Groups Below is the table of the names for the substituent groups corresponding to the boranes with n = 1 or 2 boron. For other hydroboron compounds, the substituent groups are named as follows: Boranes drop the "-ane" ending, whereas borenes drop the final "e" and replace it with the "-yl" ending (analogously to in the hydrocarbons). Branched-Chain Hydroborons These compounds are broken up into the shortest substituent groups possible, and a "parent chain" named according to the general hydroboron rules. The point at which the substituent group(s) branch(es) off the parent chain is marked with prefixed number(s) for parent chains containing at least 5 borons. For example, one isomer of quadborylene is 2-boryl-2-triborylene. Bicyclic Boranes and Borenes These boranes (containing n ≥4 boron) with 2 cycles of lengths x1 ≥x2 are named as follows: (x1, x2)-bicyclo-prefix representing n-2-borylane. With the corresponding borenes, numbers are prefixed according to the following rule: The first x1 borons are represented in counterclockwise order; this proceeds to the other borons. This rule also applies to bicyclic boranes with attached substituent groups and can be extended (using the rule that no boron can be counted twice). If this sort of compound is added to another bicyclic, a tricyclic, or a multicyclic compound, it is called a "bicycle." Tricyclic Hydroborons If the three cycles meet at one boron, then the compound (with n borons and 3 cycles of lengths x1, x2, and x3 in counterclockwise order is named (x1, x2, x3)-tricyclo-prefix representing n-2-borylane/ene, with prefixed numbers before the "ene" ending according to the rule in the section above. If the three cycles do not all meet at one boron, the cycles are ordered in "left-to-right," with the longer cycle of the two "left and right" ones assigned as "left." If this sort of compound is added to a bicyclic, a tricyclic, or a multicyclic compound, it is called a "tricycle." Multicyclic Hydroborons These compounds are divided into one of the two sorts of tricycles, as well as any leftover cycles or bicycles, and are named according to the systems for all these groups (where the substituent numbers are used for intersection points). For example, an "isomer" of pentaborylane is called "1,2-cyclomonoboryl-(5,3,3)-tricycloquadborylane." Alcohol Analogues The alcohol analogues are named as follows: with (a) prefixed number(s) (according to the rules in section 1.1.2.2 and 1.1.2.5) denoting the location of the hydroxyl group(s) when ambiguous otherwise, followed by the suffix "-ol," where the whole expression is preceded by the name of the parent compound (minus the final "ane" or "e," where the latter is in case of a parent borene). For example, one alcohol of monoborylane is monoborylan-2-ol. *Note: if there is more than one hydroxyl group, then "e-prefix representing number of groups-" is added directly after any prefixed number before the "-ol" ending. Compounds Containing Other Non-Hydroboron Substituent Groups These groups are listed in alphabetical order, and each is preceded by (a) prefixed number(s), if needed, and the bolded phrase from the Note in Section 1.1.2.8 (if needed). Nido-Hydroborons These are named the same way as the above, but with "nido" prefixed (an exception is diborane, given its own special name). Arachno-Hydroborons See "Arachno-hydroboron". Category:Boron Hypho-Hydroborons These are not covered in this Resource.